Studies of the Interaction between BSA and a Plumeran Indole Alkaloid Isolated from the Stem Bark of Aspidosperma cylindrocarpon (Apocynaceae)

Abstract

Binding between bovine serum albumin (BSA) and a plumeran indole alkaloid (PIA) isolated from the stem bark of Aspidosperma cylindrocarpon (Apocynaceae) was studied by spectroscopic techniques (UV-Vis absorption, circular dichroism, steady state and time-resolved fluorescence), combined with molecular docking. Steady state and time resolved fluorescence data revealed that PIA can quench the BSA fluorescence via a static mechanism: energy transfer from BSA to PIA occurs with high probability. The binding is strong (K b ca. 10 5 -10 6 L mol -1 ), spontaneous (ΔG° ca. -35.7 kJ mol -1 at 310 K) and entropy-driven (ΔS° = 0.146 kJ mol -1 K -1 ). There is just one main binding site (n ca. 1) for the BSA:PIA interaction and the α-helix content of the albumin does not suffer significant perturbation upon PIA binding. Molecular docking results suggest site I as the main binding site to PIA, which is able to interact with the Trp-212, Arg-217, Val-342 and Pro-446 residues.

Molecular docking analysis on the interaction between bovine serum albumin and three commercial fluoroquinolones: Ciprofloxacin, enrofloxacin and pefloxacin

“…The BSA structure is didactically divided in three homologous helical domains: I (1-179), II (180-384), and III (385-583), which show different binding abilities toward small molecules [19,21,32,37]. Is shown in Figure 2, the BSA structure presenting two internal tryptophan residues: Trp-134 located in domain I (generally known as site III) and Trp-212 located in the domain II (generally known as site I) [32,35].…”

Molecular Docking and Semi-Empirical Study of the Binding between Allura Red, a synthetic food dye, with Bovine Serum Albumin

“…Since a t-test is any statistical hypothesis test in which the test statistic follows a Student's t-distribution under the null hypothesis, it can be used to determine if two sets of data are significantly different from each other. In order to give a statistically significant difference for the theoretical results, a Student's t-test was performed: as the p value (4.03x10-9) is less than 0.05 (95% confidence interval), the null hypothesis is rejected, therefore there is a statistically significant difference between the two protein binding sites [23], and the molecular docking results suggest only one main binding site in the BSA structure for Allura red. Sudlow's site I comprises a large hydrophobic cavity, thus interactions in this site occur mainly via hydrophobic interactions.…”

In vitro Analysis of the Interaction between Human Serum Albumin and Semi‑Synthetic Clerodanes

“…The CD spectrum of HSA at physiological pH exhibits two negative bands in the ultraviolet region at 208 nm (π → π* transition) and at 222 nm (n → π* transition), which are characteristics of the α-helical content. 40 As can be seen in Figure 6, the decrease in the absorption intensity at 208 and 222 nm upon MHDCTN or PHDCTN addition indicates the destabilization of the helical structure of HSA, suggesting the occurrence of possible changes in the secondary structure of the protein.…”